DESCRIPTION: (Adapted from applicant's description) The purpose of this research is to study short-term, microgenetic processes of language acquisition, comprehension, and usage in teenagers with Down syndrome. The study derives from a theoretical framework (the Child Talk model) that emphasizes the role that prior history of talk in context plays in making language available, a history attenuated by auditory short-term memory deficits in children with Down syndrome. Experiments are proposed to (1) evaluate the role of auditory short-term memory support and to examine sentence repetition in incidental learning of novel words and in qualitative shifts in sentence comprehension strategies; (2) examine utterance formulation, turn-taking, and latency patterns in an interview format; (3) assess the discourse model s prediction of effective interventions for learning of multiple new nouns and verbs in distinctive co-occurring contexts; and acquisition of new discourse structures through repeated and expanded prompting of story telling in microgenetic studies that follow acquisition across five or six sessions.